Electronic module comprising an element exposed on one surfce and method for making same

ABSTRACT

This invention concerns a manufacturing method for an electronic module and a module manufactured according to this method that includes an assembly with two insulating sheets ( 2, 9 ) and an electronic element ( 3 ). A first insulating sheet ( 2 ) constituting one of the faces of the module including at least one window ( 4 ) in which the electronic element ( 3 ) is housed, one face of said element ( 3 ) levelling the surface of said first sheet ( 2 ) and appearing on the exterior face of the module. The second insulating sheet ( 9 ) constitutes the other face of the module. The module is characterized in that it includes an adhesive film ( 5 ) which extends over a region covering at least the outline of the window ( 4 ) of the element ( 3 ) and is situated in a region situated between the first sheet ( 2 ) and the second sheet ( 9 ).  
     The module can also include at least one electronic circuit ( 6 ) placed between the two insulating sheets ( 2, 9 ) and connected to the element ( 3 ) on the conductive connection areas ( 13 ) located on the interior face of the element ( 3 ).  
     The aim of this invention consists in avoiding the appearance of undesirable residues on the exterior face of the module in the vicinity of the element ( 3 ). These residues that originate from the infiltration of a filling material ( 8 ) through the window ( 4 ) and/or the element ( 3 ) which is housed there.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention belongs to the domain of electronic modules including anelement visible on a face and the manufacturing methods of such amodule. A module is understood as an assembly obtained by the stackingof laminated insulating layers having at least one window in which anelement is inserted. The visible face of the element levels the exteriorsurface of the module face.

The visible element is defined here either as a fixed electroniccomponent such as a visual display, a fingerprint sensor, a membraneswitch, a contact module, a solar cell, a buzzer or any other similarelement, or as a removable component such as a battery. This element canbe connected to an electronic circuit situated between two layers ofinsulating material that constitute the module faces.

The electronic circuit situated inside the module is formed by one (suchas an antenna) or several components connected to one another that serveto define the module functions. For example, in a module in the form ofa payment card without contact, the circuit is formed by a chipconnected to an antenna. Furthermore, it can be connected to a displayvisible on one of the faces of the card allowing the visualization ofdata contained in the chip such as the amount available or the debitscarried out.

A module of this type is made up of the arrangement of an electroniccircuit on a first sheet made from an insulating material and includes awindow in which an electronic component is housed. The electroniccircuit is then connected to the component then, in general, coated witha resin before laminating a second insulating sheet that will be stackedon the first. The module manufactured in this way is a sandwich made upof two insulating sheets between which the electronic circuit coatedwith binder is arranged. One face of the electronic component housed inthe window appears on one of the exterior faces of the module.

2. Description of the Prior Art

For example the document FR 2760113 describes a manufacturing method ofa combined card that can function with or without contact. The elementthat maintains the contacts is placed in a cavity formed by a window cutout of a substrate and with a bottom made up of an adhesive sheet onwhich the substrate is placed. An antenna is connected to the elementconductive areas, then the assembly is covered with a binder before theapplication of an insulating protection film. The adhesive sheet on thefirst face of the card is removed at the end of the manufacturingprocess thus allowing the appearance of the contacts on the cardsurface.

According to this method, various manufactured modules are rejectedduring the final control of production because they include residues offilling resin close to the window where the electronic component issituated. In fact, for example, when the outline of the window is largerthan that of the component, the resin fills the space left between theoutlines of the window and the component and thus the resin can spillout over the exterior face of the module. In other cases, the structureof the component can contain grooves which the resin can infiltrate bycapillary effect and contaminate the module surface. This type of moduleis discarded, or otherwise a supplementary cleaning operation would benecessary to eliminate the binding residue.

When the contact element constitutes an autonomous component, that is tosay without connection to an antenna or to other components, it can bepressed in the profiled frame of a window formed in a substrate with athickness at least equal to that of the component. The documentJP03114788 describes a method for inserting a contact element in thesubstrate of a card that including a profiled window in such a way tohold the element on the surface of one of the faces of the card. Theelement is held in the window on the face opposite to the contacts by aninsulating sheet provided with reliefs fitted onto the rear face of theelement.

Another document EP1085459 describes a manufacturing method for acontact memory card where the contact element is inserted into aprofiled frame formed in the first part of a substrate. A second flatsubstrate adhered to the first constitutes the bottom of a cavitydelimited by the outline of the frame serving to support the contactelement. The latter is inserted into the cavity in such a way that thecontacts level the surface of the face of the first substrate.

SUMMARY OF THE INVENTION

The aim of this invention is to mitigate the above-mentioned drawbacksin order to reduce the rejection rate in production. Another aim is tominimise the manufacturing costs by increasing the speed of the processwithout adversely affecting the quality of the units.

The aim is achieved thanks to a manufacturing method for an electronicmodule including at least one insulating sheet on each of its faces andat least one element having a face that levels the surface of theexterior surface of the module, characterized by the following steps:

placing a first insulating sheet on a work surface, said sheet includesat least one window in which an element will be housed,

inserting the element into the window of the insulating sheet,

stacking a protection film that extends over a region covering at leastthe outline of the window, said protection film is coated or made up ofan adhesive substance active either at room temperature or activatedunder the effect of heat and/or pressure, said protection film is calledadhesive film, laminating the previously formed assembly.

stacking then laminating a second insulating sheet on the assemblyformed by the first insulating sheet, the element and the protectionfilm, said second insulating sheet constitutes the second face of themodule.

The protection film is coated or made up of an adhesive substance whichis activated either at room temperature (self-adhesive substance) orunder the effect of heat and/or pressure. This protection film is latercalled adhesive film.

The first function of the adhesive film is to hold the element in thewindow during the handling of the assembly before proceeding to othermanufacturing steps leading to the production of a completed module.

The assembly obtained in this way can be completed using a supplementarystep which consists in directly laminating a second insulating sheetonto the adhesive film in order to form the second face of the module.The other possibility is to laminate a second assembly onto the first sothat the faces including the element turn towards the exterior. Thefinal module thus includes a visible element on each of its faces.

Depending on the thickness of the element, it is sometimes necessary tostack several insulating sheets provided with windows in order to form astack having approximately the same thickness as that of the element.The adhesive film is thus placed on a surface that has been flattenedbefore the lamination of the second sheet or of the second assembly.

According to a variant, the adhesive film can be sufficiently deformableto be applied onto an element thicker than the first insulating sheet.Supplementary insulating sheets are then stacked on this assembly inorder to compensate for the thickness of the element.

The assembly can be completed with other steps when it is necessary toinclude an electronic circuit that can be connected to the visibleelement of the module. The circuit is placed in a zone near the windowcontaining the element and is then connected to the element. A fillingmaterial is then distributed over the adhesive film, the insulatingsheet and over the electronic circuit before the lamination of a secondinsulating sheet that covers the assembly.

In this case the second face of the element facing towards the interiorof the module presents connection conductive areas allowing thesoldering of conductors for the connection with the electronic circuit.

A module assembled according to this method does not present any fillingmaterial residue on the face of the element. The adhesive film blocksall leakage in the interstices present for example between the windowoutlines and the element.

According to a variant, the adhesive film can cover the whole surface ofthe first insulating sheet, including the window where the element ishoused, and in this way prevent the infiltration of the fillingmaterial.

According to another preferred variant, the adhesive film includes awindow opposite the electrical contacts arranged on the interior face ofthe element in such a way as to facilitate the soldering of theconnections to the electronic circuit. The window dimensions are, forexample, limited to the surface area of the element corresponding to theconnection areas.

According to another variant, the first insulating sheet is providedwith a cavity that will serve to place the electronic circuit inposition. In a case where the adhesive film extends across the entiresurface of the first sheet, it would take the form of the cavity whichwould allow the placement of the circuit. This embodiment is, ingeneral, carried out when the predetermined final thickness of themodule must be respected in the case where the thickness of the circuitis more important.

This invention also has as an object an electronic module including anassembly of two insulating sheets and an element, a first insulatingsheet constituting one of the faces of the module and including at leastone window in which the element is housed, one face of said elementlevelling the surface of said first sheet and appearing on the exteriorface of the module, and the second insulating sheet constituting theother face of the module, characterized in that it includes an adhesivefilm which extends across a region covering at least the outline of thewindow of the element and being situated in a region included betweenthe first sheet and the second sheet.

The element visible on the surface of the module can be replaced by aninert core in the module manufacturing process. Once the module isfinished, the core is removed, leaving only a cavity with the form ofthe core previously inserted into one of the faces of the module. Thiscavity can be used for the subsequent insertion of a particularlyfragile component that could not withstand the temperature or thepressure of the lamination process during the manufacture of the module.In one variant, the bottom of the cavity can be provided with contactsin the form of conductive surfaces connected to the electronic circuit.These contact conductive areas are arranged on the interior face of thecore before the application of the adhesive film. They are held in thefinished module by the filling material, the adhesive film and theconnection with the circuit. Said cavity with contacts allows, forexample, the insertion of a battery, a display, a sensor or any othercomponent.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood thanks to the following detaileddescription which refers to the enclosed drawings which are given as anon-limitative example, in which:

FIG. 1 represents a top view of a module with an element inserted in awindow of the insulating sheet,

FIG. 2 represents a cross-section according to the A-A axis of themodule in FIG. 1,

FIG. 3 shows a cross-section of a variant of the module in FIG. 1 with astack of insulating sheets with a window,

FIG. 4 shows a cross-section of a module variant in which supplementarysheets are stacked after the stacking of the adhesive film on theelement,

FIG. 5 shows a cross-section of the module that includes a visibleelement on each face,

FIG. 6 represents a top view of a module including an electronic circuitbefore the application of the binder and the second insulating sheet,

FIG. 7 represents a cross-section according to the A-A axis of themodule in FIG. 5,

FIG. 8 shows a cross-section of a variant of the module in FIG. 5 with awindow in the adhesive film,

FIG. 9 shows a cross-section of a variant with a cavity in the firstinsulating sheet.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a top view of an electronic module placed on a work surface(1) which includes an element (3) such as a display, a key, a contactmodule or also an inert core. The element is inserted into an opening orwindow (4) made in the insulating sheet (2) in plastic material, theoutline of which is adapted to that of the element (3). The face of theelement (3) in contact with the work surface is at approximately thesame level as the exterior face of the module. An adhesive film (5)covers the window (4), the element (3) and an area of the insulatingsheet (2) that extends around the window (2).

FIG. 2 represents a cross-section according to the A-A axis of theassembly in FIG. 1. The thickness of the insulating sheet (2) equals thethickness of the element (3) so as to obtain an approximately flat faceafter lamination by hot or cold pressing (P) the adhesive film (5).

According to a variant shown in FIG. 3, several insulating sheets (2 a,2 b, 2 c), each including a window (4 a, 4 b, 4 c) can be stacked one ontop of the other in order to obtain the desirable thickness according tothat of the element (3). The outlines of the windows (4 a, 4 b, 4 c) ofeach sheet (2 a, 2 b, 2 c) coincide in such a way as to adapt to theoutline of the element (3). The first sheet with a window (2 a)constituting the exterior face of the module can include decoration or amarking. The adhesive film (5) is then placed on the stack (2 a, 2 b, 2c) in such a way as to cover at least the outline of the window (4 c) ofthe last sheet (2 c) of the stack. The adhesive film (5) can also extendacross the entire surface of the sheet (2 c). A second exterior sheet(9) without a window can then be directly laminated onto the adhesivefilm (5) to constitute the second face of the module that can alsoinclude decoration.

FIG. 4 represents a variant with a thicker element (3) than the firstinsulating sheet (2 a). A flexible and deformable adhesive film (5) isplaced on the element in such as way to also extend over the peripheralarea of the window (4 a) of this first sheet (2 a) where the element (3)is housed. Then the supplementary sheets (2 b, 2 c), each provided witha window (4 b, 4 c) whose outline coincides with the outline of thewindow (4 a) of the first sheet (2 a), are stacked. The thickness ofthis assembly is approximately the same as the thickness of the element(3). Finally a last sheet (9) without a window constituting the secondface of the module is assembled on the stack, covering at least theinterior face of the element (3). In this example, the main function ofthe adhesive film is to hold the element in the window of the firstsheet in order to facilitate handling. In fact, this first assemblycomprising insulating sheet with window—element—adhesive film (2 a, 3,5) can be transported to another location where the finishing works willbe carried out, this consisting in the assembly of the other sheets (2b, 2 c, 9) of the module.

FIG. 5 shows a module whose faces are provided with a visible element(3, 3′) obtained through stacking, then by assembling using the adhesionof two assemblies including insulating sheet withwindow—element—adhesive film (2, 3, 5, 2′, 3′, 5′), the faces of eachassembly provided with adhesive film (5, 5′) remaining in contact.

FIG. 6 shows a view of the assembly of a module including an electroniccircuit (6) connected to the element (3). On the work surface (1), thefirst insulating sheet (2) includes a window (4) where the element (3)is housed and is provided with two connection conductive areas (13) onits interior face. The exterior face of the element (3) like that of theinsulating sheet (2) is in contact with the work table (1). The assemblyformed by the element (3) and the insulating sheet (2) is entirelycovered by the adhesive film (5) which is provided with a window (10) inthe place where the connection conductive areas (13) of the element (3)are to be arranged. Therefore, these are released entirely to allow thesoldering of the connections (7) originating from the electronic circuit(6) placed on the adhesive film (5).

According to the variant where the element (3) is made up of an inertcore, conductive connection areas are separately placed on the interiorface of the element before the adhesive film (5) is applied. These areasare then connected to the electronic circuit (6). When the module iscompleted, the core is removed and the bottom of the resultant cavityincludes contacts. The latter allow the connection of an activecomponent, of a similar form to the removed core, which will besubsequently inserted into the cavity. The component can either beremovable like a battery, or fixed like a display, in the latter case itwill be adhered and/or pressed into the cavity, the connections with thecontacts being carried out by pressure or with a conductive adhesive forexample.

According to another variant the electronic circuit (6) includesconnections (7) that end on the internal face of the element (3) made upof an inert core so as to form contact areas on the bottom of the cavitywhen the core is removed.

The cross-section in FIG. 7, according to the A-A axis, shows thestacking of the different elements of a module before pressing orlamination which are carried out according to the arrows P. Theelectronic circuit (6) is placed on the adhesive film (5) close to thewindow (4) in order to facilitate its connection to the element (3).This circuit (6) can also surround the element (3) if it deals forexample with an antenna of any type connected to a chip, the latterwould be placed next to the element. In other cases, parts of thecircuit (6) can partially cover the element (3) when for example thesurface available becomes small due to the large exterior dimensions ofthe circuit compared to those of the module. The position of the circuit(6) is maintained by adhesion on the adhesive film (5). A layer offilling material (8) is then distributed if necessary over all or partof the surface of the adhesive film (5) and the electronic circuit (6).

Filling material is understood to mean a substance in the form of aliquid or pasty resin, a thermo-fusible film or also a porous andflexible element that can be coated with an adhesive substance (foam,plastic material agglomerate). The function of said material is to fillin the holes and compensate the surface reliefs due to the assembly ofthe different elements of the module. According to its nature and itschemical composition this material is capable of solidifying, forexample, under a cooling, heating or a UV radiation action.

Finally, a second insulating sheet (9) constituting the other face ofthe module is stacked and then pressed (P) onto the filling layer (8).Each of these insulating sheets (2, 9) can include a decoration on itsexterior faces which also constitute the exterior faces of the module.

The manufacturing method of a module includes at least one element (3)having a first face that levels the exterior surface of the module, anda second face presenting the conductive connection areas (13) and anelectronic circuit (6) is characterized by the following supplementarysteps:

placing an electronic circuit (6) in a zone near the window (4)containing the element (3),

connecting the connections areas (13) of the element (3) to theelectronic circuit (6),

distributing a layer of filling material (8) onto the adhesive film (5),on the first insulating sheet (2) and on the electronic circuit (6),

stacking a second insulating sheet (9) on the layer of filling material(8),

laminating the previously formed assembly.

This process begins with the three first steps relating to those of themanufacturing method of the module without the electronic circuit (6) asdescribed above. The supplementary steps concern the placing of thecircuit (6), its connection to the visible element (3) and coating withthe filling material (8), thus assuring its protection and themaintenance of the module.

The adhesive film (5) has the double function of protecting the element(3) and the window (4) against the undesirable penetration of fillingmaterial (8), as well as to maintain the position of the electroniccircuit (6) during the assembly of the module.

FIG. 8 shows a variant where the adhesive film (5) includes a window(10) to be positioned opposite the conductive connection areas (13) ofthe element (3). The outline of the window (10) adapts to the outline ofthe areas of the interior face of the element (3) occupied by theconnection areas (13). For example, the outline of the window (10) cansurround a group of several contacts or surround each contact areaindividually. The aim of this window (10) is to leave the connectionareas (13) free of any substance that could impede the soldering of theconnections (7) in order to connect the element (3) to the electroniccircuit (6). The window (10) is formed before the application of theadhesive film (5) onto the first insulating sheet (2) either by stampingor cutting, or by chemical etching.

According to the variant shown in FIG. 7 where the adhesive film (5) iswithout a window, welding is possible because certain materialsconstituting the adhesive film (5) evaporate completely due to the heatof the soldering process without leaving deposits on the connectionareas (13).

FIG. 9 shows a variant with a cavity (11) cut into the first insulatingsheet (2), the outline of which adapts to that of the electronic circuit(6). This cavity is in general milled before or after the formation ofthe window (4) destined to receive the element (3). The depth of thecavity (11) depends on the thickness of the first sheet (2) and thethickness of the electronic circuit (6) which will be placed and adheredonto the adhesive film (5) which covers the bottom of the cavity (11).The final thickness of a module can be imposed by the applicationstandards or restrictions, the cavity (11) allowing the integration of athicker circuit (6) in the module without exceeding the predetermineddimension.

The cavity (11) can also be formed by one opening or the stacking ofopenings in one or various intermediate sheets (2 b, 2 c) stacked thenlaminated onto the first sheet (2, 2 a). Each of these sheets alsoincludes a window (4, 4 a, 4 b, 4 c) for the element (3), see theexample in FIG. 3.

According to a variant of the invention method, the adhesive film (5)can be placed in a first phase directly onto the work surface (1). Thewindow (10) destined to free the connection areas (13) of the element(3) is then formed before placing in position the electronic circuit(6). The circuit film assembly is then transferred to another locationwhere the first insulating sheet (2) provided with the window (4)containing the element (3) is applied. The steps for the connection ofthe element (3) to the circuit (6), providing the filling material (8)and lamination of the second insulating sheet (9) are carried out in thesame way as the process previously described. This variant of the methodallows the increase of the production speed thanks to the simultaneityof the first steps. For example, the stamping of the window (4) and themilling of the cavity (11) in the first insulating sheet (2) as well asthe placement of the element (3) in the window (4) can be carried out atthe same time as the stamping of the window (10) in the adhesive film(5) and the positioning of the electronic circuit (6) on the film (5).

1. Manufacturing method of an electronic module including at least oneinsulating sheet on each of its faces and at least one element having alevelled face on the exterior surface of the module, comprising thefollowing steps: placing a first insulating sheet on a work surface,said sheet includes at least one window in which an element will behoused, inserting the element in the window of the insulating sheet,stacking a protection film extending over a region covering at least theoutline of the window, said protection film is coated or made up of anadhesive substance active either at room temperature, or activated underthe effect of heat and/or pressure, said protection film is calledadhesive film, laminating the assembly previously formed. stacking thenlaminating a second insulating sheet on the assembly formed by the firstinsulating sheet, the element and the protection film, said secondinsulating sheet constituting the second face of the module.
 2. Methodaccording to claim 1 wherein the outline of the window of the insulatingsheet adapts to the outline of the element.
 3. Manufacturing method of amodule according to claim 1, wherein the element is thicker than a firstinsulating sheet and housed in the window, and several insulating sheetsare stacked, with the outlines of the windows of each sheet coinciding,and the total thickness of the stack being approximately the same asthat of the element housed in the windows of each sheet, the adhesivefilm being placed on the stack by covering at least the outline of thewindow of the last sheet of the stack.
 4. Manufacturing method of amodule according to claim 1, wherein the element is thicker than a firstinsulating sheet and housed in the window, and the adhesive film isplaced on the element in such a way as to also extend over the outlineof the window of said first sheet, the supplementary sheets eachprovided with a window are stacked, the outline of the windows of eachsheet coinciding with the outline of the window of the first sheet, andthe thickness of the assembly of sheets is approximately the same as thethickness of the element.
 5. Method according to claim 3, wherein asecond insulating sheet is stacked then laminated onto the assemblyformed by the first sheet(s), the element and the protection film, saidsecond insulating sheet constituting the second face of the module. 6.Method according to claim 1, wherein the element inserted in the windowof the insulating sheet is made up of an electronic component.
 7. Methodaccording to claim 1, wherein the element inserted in the window of theinsulating sheet is constituted by an inert core to be removed at theend of the module manufacturing process, leaving a cavity having theform of the core previously inserted on one of the faces of said module,said cavity being used for the subsequent insertion of an electroniccomponent.
 8. Module manufacturing method according to claim 6, whereinthe element has a first face that levels the exterior surface of themodule, and a second face presenting the conductive areas forconnection, the module furthermore including an electronic circuit,comprising the following supplementary steps that are carried out afterthe stacking of the protection film: placing the electronic circuit inan area near the window containing the element, connecting theconnection areas of the element to the electronic circuit, distributinga layer of filling material over the protection film, over theinsulating sheet and over the electronic circuit, stacking a secondinsulating sheet on the layer of filling material, laminating thepreviously formed assembly.
 9. Module manufacturing method according toclaim 7, said module including an electronic circuit, comprising thefollowing supplementary steps that are carried out after the stacking ofthe protection film: placing the electronic circuit in an area near thewindow containing the element, distributing a layer of filling materialover the protection film, over the insulating sheet and over theelectronic circuit, stacking a second insulating sheet on the layer offilling material, laminating the previously formed assembly.
 10. Methodaccording to claim 9, wherein, prior to the distribution of the fillingmaterial layer, conductive connection areas are placed on the interiorface of the element opposite the face that levels the exterior surfaceof the module, said connection areas are then connected to theelectronic circuit.
 11. Method according to claim 9, wherein theelectronic circuit includes connections ending on the interior face ofthe element opposite the face that levels the exterior surface of themodule.
 12. Method according to claim 8, wherein, prior to theapplication of the protection film on the insulating sheet and elementassembly, the electronic circuit is placed on said protection film andthe protection film and electronic circuit assembly is applied onto theinsulating sheet and element assembly.
 13. Method according to claim 8wherein the protection film includes at least one window situatedopposite the connection areas of the element.
 14. Method according toclaim 8, wherein the first insulating sheet includes a cavity, theoutline of said cavity being adapted to the outline of the electroniccircuit which will be placed in said cavity.
 15. Electronic moduleincluding an assembly of two insulating sheets and an element, a firstinsulating sheet constituting one of the faces of the module includingat least one window in which the element is housed, one face of saidelement levelling the surface of said first sheet and appearing on theexterior face of the module, and the second insulating sheetconstituting the other face of the module, wherein an adhesive film,which extends over a region covering at least the outline of the windowof the element and is located in a region between the first sheet andthe second sheet.
 16. Electronic module according to claim 15, includingat least one electronic circuit placed between both insulating sheetsand is connected to the element on the connection conduction areassituated on the interior face of the element.
 17. Electronic moduleaccording to claim 15, wherein the adhesive film includes a windowopposite the conductive connection areas of the element, the outline ofsaid window being adapted to the outline of the zone occupied by saidconnection areas.
 18. Electronic module according to claim 16, wherein alayer of filling material extends between both insulating sheets andcovers all or part of the adhesive film and the electronic circuit. 19.Electronic module according to claim 15, wherein the exterior faces ofthe insulating sheets constituting the exterior module faces include adecoration or a marking.
 20. Electronic module according to claim 15,wherein the element is constituted by an inert core to be removedleaving a cavity taking the form of the previously inserted core, on oneof the faces of said module, said cavity to be used for the subsequentinsertion of a fixed or removable electronic component.
 21. Electronicmodule according to claim 20, wherein the bottom of the resultantcavity, after the element has been removed, includes conductive contactareas connected to the electronic circuit.
 22. Electronic moduleaccording to claim 15, wherein the element is constituted by anelectronic component.
 23. Method according to claim 4, wherein a secondinsulating sheet is stacked then laminated onto the assembly formed bythe first sheet(s), the element and the protection film, said secondinsulating sheet constituting the second face of the module.
 24. Methodaccording to claim 9, wherein, prior to the application of theprotection film on the insulating sheet and element assembly, theelectronic circuit is placed on said protection film and the protectionfilm and electronic circuit assembly is applied onto the insulatingsheet and element assembly.